Transmission, Hybrid Drive Train, and Drive Train for an Electric Vehicle

ABSTRACT

Transmission (G) with a transmission input shaft (GW 1 ) and a transmission output shaft (GW 2 ), a main gear set (HRS), an auxiliary gear set (ZRS), and an electric motor (EM) with a rotor (R) and a stator (S), whereas the transmission (G) features at least one power path (L 1,  L 2,  L 3 ) between the transmission input shaft (GW 1 ) and the main gear set (HRS), whereas the main gear set (HRS) features a first and a second planetary gear set (P 1,  P 2 ) with a total of four shafts (W 1,  W 2,  W 3,  W 4 ) designated in the order of rotational speeds as the first, second, third and fourth shafts, whereas the at least one power path (L 1,  L 2,  L 3 ) is connectable through at least one shift element (A, B, C, D, E) to at least one of the four shafts (W 1,  W 2,  W 3,  W 4 ) of the main gear set (HRS), whereas the second or the third shaft (W 2,  W 3 ) of the main gear set (HRS) is connected to the transmission output shaft (GW 2 ), whereas the auxiliary gear set (ZRS) features a planetary gear set (P 4 ) with a first, second and third shafts (W 1 P 4,  W 2 P 4,  W 3 P 4 ), and whereas the first shaft (W 1 P 4 ) of the auxiliary gear set (ZRS) is connected to the rotor (R), whereas the second shaft (W 2 P 4 ) of the auxiliary gear set (ZRS) is constantly connected to the first shaft (W 1 ) of the main gear set (HRS), and whereas the third shaft (W 3 P 4 ) of the auxiliary gear set (ZRS) is constantly connected to the second, third or fourth shafts (W 2,  W 3,  W 4 ) of the main gear set (HRS).

The invention relates to a transmission with a transmission input shaft and a transmission output shaft, a main gear set, an auxiliary gear set, and an electric motor with a rotor and a stator, whereas the transmission comprises at least one power path between the transmission input shaft and the main gear set, whereas the main gear set features a first and a second planetary gear set with a total of four shafts designated in the order of rotational speeds as the first, second, third and fourth shafts, whereas the at least one power path is connectable through at least one shift element to at least one of the four shafts of the main gear set, whereas the third shaft of the main gear set is connected to the transmission output shaft, and whereas the auxiliary gear set features a planetary gear set with a first, second and third shafts, whereas the first shaft of the auxiliary gear set is connected to the rotor. The invention also relates to a drive train for a motor vehicle with a transmission.

Herein, a transmission in particular designates a multi-speed transmission, with which a predetermined number of gears, thus fixed transmission ratio relationships between a transmission input shaft and a transmission output shaft, are automatically shiftable by means of shift elements. Herein, the shift elements comprise, for example, clutches or brakes. Such transmissions are primarily used in automotive applications, in order to adjust the rotational speed and torque output capabilities of the drive unit to the driving resistance of the motor vehicle in a suitable manner.

From patent application DE 10 2012 201 377 A1 of the applicant, a transmission with a transmission input shaft and a transmission output shaft, and two power paths between the transmission input shaft and a main gear set with two individual planetary gear sets, with four shafts designated in the order of rotational speeds as the first, second, third and fourth shafts is known, whereas the third of the four shafts is connected to the transmission output shaft. An electric motor is connected through a planetary transmission at the first shaft of the main gear set.

The task of the invention is to improve the load-shifting behavior of the transmission known in the state of the art.

An additional task of the invention is to improve the operating range of the transmission, such that, in any gear, the electric motor is able to receive mechanical power from the transmission output shaft or deliver power to it.

The tasks are solved by the characteristics of claim 1, whereas advantageous embodiments arise from the sub-claims, the description and the figures.

The transmission comprises at least one transmission input shaft and a transmission output shaft, a main gear set, an auxiliary gear set, and an electric motor with a rotor and a stator.

The main gear set features a first and a second planetary gear set with a total of four shafts designated in the order of rotational speeds as the first, second, third and fourth shafts. The main gear set is thus formed as a two-bar/four-shaft transmission. The auxiliary gear set features a planetary gear set with a total of three shafts designated as the first, second and third shafts. The first shaft of the auxiliary gear set is constantly connected to the rotor.

A “two-bar/four-shaft transmission” is understood to be a planetary transmission that is formed from two individual planetary gear sets kinematically coupled with each other through exactly two coupling shafts, and with which four of its elements (“shafts”) are freely accessible for other transmission elements. Thereby, a coupling shaft is defined as a constant mechanical connection between one element—thus, a sun gear or a bar or a ring gear—of the first individual planetary gear set with one element—thus, a sun gear or a bar or a ring gear—of the second individual planetary gear set. The number of individual planetary gear sets and the number of free shafts are not defined by the visual appearance of the transmission, but through its kinematics. In each gear of a two-bar/four-shaft transmission, two of the shift elements of the transmission connected to elements of the two-bar/four-shaft transmission must be locked. For the graphical representation of the kinematics of the transmission, a rotational speed diagram of the transmission (for example, the Kutzbach diagram known from transmission theory) is typically used. Known embodiments of such a two-bar/four-shaft transmission include the so-called “Ravigneaux gear set” and the so-called “Simpson gear set.”

A reduced two-bar/four-shaft transmission is a structural shape of a two-bar/four-shaft transmission in which one element—that is, a sun gear, a bar or a ring gear—of the transmission is spared, since another element of the transmission takes over its task, without thereby changing the kinematics. That element that takes over the function of the spared element is thus one of the coupling shafts of the transmission at the same time. A known embodiment of this is the Ravigneaux gear set, which features either two sun gears and only one ring gear, or two ring gears and only one sun gear.

Through at least one power path, the transmission input shaft is connectable through at least one shift element to at least one of the four shafts of the main gear set. In a preferred embodiment, the at least one power path is connectable through two shift elements to two of the four shafts of the main gear set. By locking one of the shift elements, a torque-proof connection between the at least one power path and one of the four shafts of the main gear set is thus established, by which torque can be led from the transmission input shaft to the main gear set. “At least one power path” is to be understood such that the transmission features one or more power paths between the transmission input shaft and the main gear set. The third shaft of the main gear set is thereby connected to the transmission output shaft.

In accordance with the invention, the second shaft of the auxiliary gear set is constantly connected to the first shaft of the main gear set. The third shaft of the auxiliary gear set is constantly connected to the second, third or fourth shafts of the main gear set.

Upon use in a motor vehicle, the transmission input shaft is connectable to a shaft of a drive unit, or is connectable through a clutch, such that mechanical power of the drive unit can be supplied to the transmission input shaft. The drive unit may be formed as an internal combustion engine and as an electric motor. The transmission output shaft serves as an interface for transferring mechanical power to the drive wheels of the motor vehicle.

In the following, a “shaft” is not solely understood as an exemplary cylindrical, rotatably mounted machine element for the transfer of torques, but is also understood as a general connection element, which connects individual components or elements to each other, in particular connection elements that connect several elements to each other in a torque-proof manner.

A planetary gear set comprises a sun gear, a bar and a ring gear. Planetary gears, which mesh with the toothing of the sun gear and/or with the toothing of the ring gear, are rotatably mounted on the bar. In the following, a negative gear set describes a planetary gear set with a bar, on which the planetary gears are rotatably mounted, with a sun gear and a ring gear, whereas the toothing of at least one of one of the planetary gears meshes both with the toothing of the sun gear and with the toothing of the ring gear, by which the ring gear and the sun gear rotate in opposite directions of rotation, if the sun gear rotates with a fixed bar.

Both sun gear and ring gear of a planetary gear set can also be divided into several segments. For example, it is conceivable that the planet gears mesh with two sun gears, which are not connected to each other. Of course, the rotational speed relationships are identical on both segments of the sun gear, as if they were connected to each other.

A positive gear set differs from the negative planetary gear set just described in that the positive gear set features inner and outer planetary gears, which are rotatably mounted on the bar. Thereby, the toothing of the inner planetary gears meshes, on the one hand, with the toothing of the sun gear and, on the other hand, with the toothing of the outer planetary gears. In addition, the toothing of the outer planetary gears meshes with the toothing of the ring gear. This has the consequence that, with a fixed bar, the ring gear and the sun gear rotate in the same direction of rotation.

The stationary transmission ratio defines the rotational speed relationship between the sun gear and ring gear of a planetary gear with a torque-proof bar. Since, with a negative gear set, the direction of rotation between the sun gear and ring gear with a torque-proof bar is reversed, the stationary transmission ratio always increases to a negative value with a negative gear set.

In the rotational speed diagram, the rotational speed relationships of the individual shafts are plotted in a vertical direction. The horizontal gaps between the shafts arise from the transmission ratio relationships between the shafts, such that rotational speed relationships and torque relationships of the shafts pertaining to a given operating point can be connected by a straight line. The transmission ratio relationship between the shafts arise from the stationary transmission ratios of the planetary gear sets involved. The rotational speed diagram can be presented, for example, in the form of a Kutzbach diagram.

Four shafts designated in the order of rotational speeds as the first, second, third and fourth shafts are characterized in that the rotational speeds of such shafts in the specified sequence increase, decrease or are equal in a linear manner. In other words, the rotational speed of the first shaft is less than or equal to the rotational speed of the second shaft. In turn, the rotational speed of the second shaft is less than or equal to the rotational speed of the third shaft. The rotational speed of the third shaft is less than or equal to the rotational speed of the fourth shaft. This sequence is also reversible, such that the fourth shaft features the highest speed, while the first shaft assumes a rotational speed that is less than or equal to the rotational speed of the fourth shaft. Thereby, there is always a linear relationship between the rotational speeds of all four shafts.

Thereby, the rotational speed of one or more shafts can also assume negative values, or even the value of zero. Therefore, the order of rotational speeds is always to refer to the signed value of the rotational speeds, and not to their amount.

The rotational speeds of the four shafts are equal if, of the elements ring gear, bar and sun of one of the planetary gear sets, two of such elements are connected to each other.

An electric motor consists of at least one torque-proof stator and one rotatably mounted rotor, and, during engine mode, is configured to convert electrical energy into mechanical energy in the form of rotational speed and torque, and, during generator mode, to convert mechanical energy into electrical energy in the form of current and voltage.

Through shift elements, depending on their operating state, a relative movement between two components is enabled, or a connection for the transmission of a torque between the two components is established. A “relative movement” is understood as, for example, a rotation of two components, whereas the rotational speed of the first component and the rotational speed of the second component differ from each other. In addition, the rotation of only one of the two components is conceivable, while the other component is at a standstill or rotates in the opposite direction. In the subject invention, the shift elements are preferably designed as claw-shift elements, which establish the connection by means of a positive connection.

Two elements are referred to as connected to each other particularly if there is a fixed (in particular, torque-proof) connection between the elements. Such connected elements rotate with the same rotational speed. The various components and elements of the specified invention may be connected to each other through a shaft or through a locked shift element or a connection element, or also directly, for example by means of a welded connection, a crimping connection or another connection.

Furthermore, two elements are described as connectable if there is a detachably torque-proof connection between such elements. If the connection exists, such elements rotate with the same rotational speed.

A shifting process is effected by locking a shift element of the transmission that was previously not located in the power flow of the transmission, and opening a shift element of the transmission previously located in the power flow of the transmission. The shifting process may also be undertaken under load, that is without a complete withdrawal of the torque at the transmission input shaft and the transmission output shaft. Such a shifting process is hereinafter referred to as a “load shift.” With the use of claw-shift elements, a requirement for a load shift is that the shift element to be released is guided into a state that is at least nearly load-free prior to its release. The guiding into the state that is nearly load-free is achieved by the fact that the shift element is made largely free of torque, such that, through the shift element, no torque or only a small torque is transferred. For this purpose, through the electric motor, a torque is applied at that shaft with which the shift element to be released establishes a connection.

Through the connection in accordance with the invention of the rotor to the main gear set, it is thereby achieved that the transmission ratio of the rotor at the shafts of the main gear set is increased. In other words, through the connection in accordance with the invention, the first shaft of the main gear set in the rotational speed diagram is always located between the first shaft of the auxiliary gear set and the second shaft of the main gear set. Through this enlarged transmission ratio, the torque to be applied by the rotor during the shifting process is reduced, by which the electric motor can be constructed smaller and lighter. In such a manner, with a load shift, the scaled-down electric motor may, even with a high torque at the transmission input shaft, apply the necessary torque, without leading to an undesirably high reduction in torque at the transmission output shaft. The enlarged transmission ratio is also useful if the torque of the electric motor is to be transferred to the transmission output shaft (for example, when using the transmission in a motor vehicle), by which an electric driving mode of the motor vehicle is enabled. Through the transmission ratio enlarged in such a manner, a start-up of the motor vehicle into an incline is possible even with a scaled-down electric motor. The enlarged transmission ratio is also useful if, starting from the electric motor, a torque is transferred to the transmission input shaft, for example when used for starting an internal combustion engine that is connected to the transmission input shaft. Moreover, the enlarged transmission ratio leads to the fact that the electric motor is smaller, and thus can be more easily built.

Through the allocation in accordance with the invention of the shafts of the main gear set to the second and third shafts of the auxiliary gear set, it is also achieved that the rotor, even with a torque-proof fixing of the first shaft of the main gear set, is able to assume a rotational speed. This is a prerequisite for the electric motor to receive and deliver mechanical power. It is thereby enabled that the electric motor is capable of receiving or delivering mechanical power in those gears in which the first shaft of the main gear set is fixed in a torque-proof manner or does not have an appreciable rotational speed. This is particularly advantageous when using the transmission in a motor vehicle, since kinetic energy of the motor vehicle can be recuperated in each gear of the transmission through the generator mode of the electric motor. If an internal combustion engine is connected to the transmission input shaft, the load point of the internal combustion engine can also be displaced in any gear by means of the generator mode or engine mode of the electric motor. Thus, the transmission enables an increase in efficiency of the motor vehicle.

Preferably, a sun gear of the planetary gear set of the auxiliary gear set is a component of the first shaft of the auxiliary gear set. In the event that the planetary gear set of the auxiliary gear set is formed as a negative gear set, a bar of the planetary gear set of the auxiliary gear set is a component of the second shaft of the auxiliary gear set, and a ring gear of the planetary gear set of the auxiliary gear set is a component of the third shaft of the auxiliary gear set. If the planetary gear set of the auxiliary gear set is formed as a positive gear set, the allocation of the ring gear and the bar is interchanged, such that the ring gear of the planetary gear set of the auxiliary gear set is a component of the second shaft of the auxiliary gear set, and the bar of the planetary gear set of the auxiliary gear set is a component of the third shaft of the auxiliary gear set.

However, the allocation of the planetary gear set of the auxiliary gear set to the main gear set may also take place in mirrored form, by the sun gear of the planetary gear set of the auxiliary gear set being a component of the third shaft of the auxiliary gear set. If the planetary gear set of the auxiliary gear set is thereby formed as a negative gear set, the bar of the planetary gear set of the auxiliary gear set is a component of the second shaft of the auxiliary gear set, and the ring gear of the planetary gear set of the auxiliary gear set is a component of the first shaft of the auxiliary gear set. If the planetary gear set of the auxiliary gear set is formed as a positive gear set, the allocation of the ring gear and the bar is interchanged, such that the ring gear of the planetary gear set of the auxiliary gear set is a component of the second shaft of the auxiliary gear set, and the bar of the planetary gear set of the auxiliary gear set is a component of the first shaft of the auxiliary gear set.

Through the multiple number of options offered for the connection between the rotor, the auxiliary gear set and the main gear set, the invention is particularly easily adjustable for various transmission variants and available installation space ratios.

The sequence of the four shafts of the main gear set in the rotational speed diagram depends on the manner in which shafts are allocated to which elements of the first and second planetary gear sets of the main gear set, and which of the four shafts are connected to each other. Examples of this are known in the state of the art, but certain variations have emerged as particularly advantageous for implementation in a transmission. These are particularly advantageous based on a geometrically favorable arrangement, based on reduced component stress and based on improved accessibility to the shift elements.

In accordance with a first preferred variant, the first shaft of the main gear set is connected to a sun gear of the first planetary gear set of the main gear set. The second shaft of the main gear set is connected to a bar of the first planetary gear set and to a ring gear of the second planetary gear set of the main gear set. The third shaft of the main gear set is connected to a ring gear of the first planetary gear set and to a bar of the second planetary gear set of the main gear set. The fourth shaft of the main gear set is connected to a sun gear of the second planetary gear set of the main gear set. Thereby, the first and second planetary gear sets are formed as a negative gear sets.

In accordance with a second preferred variant, the first shaft of the main gear set is connected to the sun gear of the first planetary gear set and to the sun gear of the second planetary gear set of the main gear set. The second shaft of the main gear set is connected to the bar of the first planetary gear set of the main gear set. The third shaft of the main gear set is connected to the ring gear of the first planetary gear set of the main gear set and to the bar of the second planetary gear set of the main gear set. The fourth shaft of the main gear set is connected to the ring gear of the second planetary gear set of the main gear set. Thereby, the first and second planetary gear sets are formed as a negative gear sets.

In accordance with a third preferred variant, the first shaft of the main gear set is connected to the sun gear of the first planetary gear set of the main gear set. The second shaft of the main gear set is connected to the bar of the first and the second planetary gear sets of the main gear set. The third shaft of the main gear set is connected to the ring gear of the first and second planetary gear sets of the main gear set. The fourth shaft of the main gear set is connected to the sun gear of the second planetary gear set of the main gear set. Thereby, the first planetary gear set is formed as a negative gear set, while the second planetary gear set is formed as a positive gear set.

In accordance with a fourth preferred variant, the first shaft of the main gear set is connected to the sun gears of the first and second planetary gear sets of the main gear set. The second shaft of the main gear set is connected to the bar of the second planetary gear set of the main gear set. The third shaft of the main gear set is connected to the bar of the first planetary gear set and to the ring gear of the second planetary gear set of the main gear set. The fourth shaft of the main gear set is connected to the ring gear of the first planetary gear set of the main gear set. Thereby, the first and second planetary gear sets are formed as a negative gear sets.

In accordance with a fifth preferred variant, the first shaft of the main gear set is connected to the sun gear of the first planetary gear set of the main gear set. The second shaft of the main gear set is connected to the bar of the first planetary gear set and to the ring gear of the second planetary gear set of the main gear set. The third shaft of the main gear set is connected to the bar of the second planetary gear set of the main gear set. The fourth shaft of the main gear set is connected to the ring gear of the first planetary gear set and the sun gear with the second planetary gear set of the main gear set. Thereby, the first and second planetary gear sets are formed as negative gear sets.

Preferably, the transmission may be a component of a hybrid drive train of a motor vehicle. The hybrid drive train features an internal combustion engine, in addition to the transmission. The internal combustion engine is connected or connectable, either directly or through a clutch, to the transmission input shaft of the transmission. The motor vehicle may be driven by both the internal combustion engine and the electric motor of the transmission. Optionally, the transmission features an auxiliary electric motor, which is configured, through its rotor, to deliver torque to the transmission input shaft and, in such a way, start the internal combustion engine. This has the advantage that the internal combustion engine can be started by means of the auxiliary electric motor, without having any influence on a simultaneous electric driving mode, by the motor vehicle being driven solely by the electric motor of the transmission.

The electric motor is thereby connected to a converter, through which the electric motor is connected to an energy storage device. For this purpose, any form of energy storage device (in particular, an electrochemical, electrostatic, hydraulic or mechanical energy storage device) is suitable.

In an additional embodiment, the transmission may also be a component of a drive train of an electric motor vehicle. An electric motor vehicle is driven solely by one or more electric motors, and accordingly has no internal combustion engine. In this case, a traction electric motor is connected to the transmission input shaft. Through the different transmission ratio stages of the transmission, the traction electric motor may always be operated in an operating range with a high degree of efficiency, by which the energy efficiency of the entire electric motor vehicle is improved.

Embodiments of the invention are described in detail on the basis of the attached figures.

FIG. 1 schematically shows a transmission in accordance with a first embodiment of the invention.

FIG. 2 shows a rotational speed diagram of the transmission in accordance with the first and second embodiments.

FIG. 3 shows a shifting diagram of the transmission in accordance with the first and second embodiments.

FIG. 4 schematically shows a transmission in accordance with one variant of the first embodiment of the invention.

FIG. 5 schematically shows a transmission in accordance with a second embodiment of the invention.

FIG. 6 shows a rotational speed diagram of the transmission in accordance with the second embodiment.

FIG. 7 shows a shifting diagram of the transmission in accordance with the second embodiment.

FIG. 8 schematically shows a transmission in accordance with a first variant of the second embodiment of the invention.

FIG. 9 schematically shows a transmission in accordance with a second variant of the second embodiment of the invention.

FIG. 10 schematically shows a transmission in accordance with a third embodiment of the invention.

FIG. 11 shows a rotational speed diagram of the transmission in accordance with the third embodiment.

FIG. 12 shows a shifting diagram of the transmission in accordance with the third embodiment.

FIG. 13 shows a hybrid drive train of a motor vehicle.

At the outset, it must be stated that, in the various described embodiments, the same parts are provided with the same reference signs or the same component names, whereby the disclosures contained throughout the description can be transferred analogously to the same parts with the same reference signs or the same component names.

FIG. 1 schematically shows a transmission G in accordance with a first embodiment of the invention. The transmission G features a transmission input shaft GW1, a transmission output shaft GW2, an upstream gear set VRS, an auxiliary gear set ZRS and a main gear set HRS. The upstream gear set VRS features a first planetary gear set P3 and a second planetary gear set P5. The auxiliary gear set ZRS features a planetary gear set P4, while the main gear set HRS features a first planetary gear set P1 and a second planetary gear set P2. All planetary gear sets P1, P2, P3, P4, P5 are formed as negative gear sets.

The representation of the transmission essentially shows the connectable and connected elements of the transmission G. Conclusions regarding the transmission ratio relationships cannot be drawn by the distances selected in the representation of the transmission.

The upstream gear set VRS features four shafts W1VS, W2VS, W3VS and W4VS designated in the order of rotational speeds as the first, second, third and fourth shafts. A first power path L1 is led through the second shaft W2VS of the upstream gear set VRS, which is connected to a bar St-P3 of the first planetary gear set P3 of the upstream gear set VRS and to a sun gear So-P5 of the second planetary gear set P5 of the upstream gear set P5. A sun gear So-P3 of the first planetary gear set P3 of the upstream gear set VRS is a component of the first shaft W1VS of the upstream gear set VRS and is fixed in a torque-proof manner, while a ring gear Ho-P3 of the first planetary gear set P3 of the upstream gear set VRS and a bar St-P5 of the second planetary gear set P5 of the upstream gear set VRS are connected to the transmission input shaft GW1. The third shaft W3VS of the upstream gear set VRS is connected to the transmission input shaft GW1, and is also a component of the second power path L2. A third power path L3 is led through the fourth shaft W4VS of the upstream gear set VRS, whereas a ring gear Ho-P5 of the second planetary gear set P5 of the upstream gear set VRS is a component of the fourth shaft W4VS of the upstream gear set VRS. A sun gear So-P5 of the second planetary gear set P5 of the upstream gear set VRS is thereby connected to the second shaft W2VS of the upstream gear set VRS.

A first shaft W1 of the main gear set HRS is connected to a sun gear So-P1 of the first planetary gear set P1 and to a sun gear So-P2 of the second planetary gear set P2 of the main gear set HRS. A second shaft W2 of the main gear set HRS is connected to a bar St-P1 of the first planetary gear set P1. A third shaft W3 of the main gear set HRS is connected to a ring gear Ho-P1 of the first planetary gear set P1 and to a bar St-P2 of the second planetary gear set P2 of the main gear set HRS. A fourth shaft W4 of the main gear set HRS is connected to a ring gear Ho-P2 of the second planetary gear set P2 of the main gear set HRS. Through this arrangement and connection between the individual components of the first and second planetary gear sets P1, P2 of the main gear set HRS, the arrangement of the first, second, third and fourth shafts W1, W2, W3, W4 of the main gear set HRS in the rotational speed diagram is determined, whereas the sequence of first, second, third, fourth shafts W1, W2, W3, W4 corresponds to their sequence in the rotational speed diagram. The third shaft W3 is connected to the transmission output shaft GW2. Alternatively, the third shaft W3 may also be connected through an additional transmission gearing to the transmission output shaft GW2.

Thereby, the sun gear So-P1 of the first planetary gear set P1 and the ring gear of the second planetary gear set P2 of the main gear set HRS feature two separate parts. The division of the ring gear Ho-P2 facilitates the connection of the transmission output shaft GW2 to the third shaft W3 of the main gear set, which is arranged between the two parts of the ring gear Ho-P2. Of course, the rotational speed relationships are the same on both parts of the ring gear Ho-P2. Consequently, hereinafter, both parts of the ring gear Ho-P2 are referred to as one component of the same shaft, specifically the fourth shaft W4 of the main gear set HRS. The division of the sun gear So-P1 facilitates the connection of the upstream gear set VRS to the second shaft W2 of the main gear set HRS. Here as well, the rotational speed relationships are, of course, identical with the two parts of the sun gear So-P1, such that the two parts of the sun gear So-P1 are considered one component of the first shaft W1 of the main gear set.

The first power path L1 is connectable through a fourth shift element D to the second shaft W2 of the main gear set HRS and through a fifth shift element C to the first shaft W1 of the main gear set HRS. The second power path L2 is connectable through a first shift element A to the fourth shaft W4 of the main gear set HRS and through a third shift element B to the first shaft W1 of the main gear set HRS. The third power path L3 is connectable through a second shift element E to the second shaft W2 of the main gear set HRS. Through a sixth shift element F, the fourth shaft W4 of the main gear set HRS is fixed in a torque-proof manner, by the fourth shaft W4 being connected through the sixth shift element F to the transmission housing GG.

The transmission G features an electric motor EM, whereas a stator S is connected in a torque-proof manner to the transmission housing GG of the transmission G or to another torque-proof component of the transmission G, such that the stator S cannot assume any rotational speed. A rotatably mounted rotor R is connected to a ring gear Ho-P4 of the planetary gear set P4 of the auxiliary gear set ZRS. The ring gear Ho-P4 of the planetary gear set P4 of the auxiliary gear set ZRS is a component of a first shaft W1P4 of the auxiliary gear set ZRS. A bar St-P4 of the planetary gear set P4 of the auxiliary gear set ZRS is a component of a second shaft W2P4 of the auxiliary gear set ZRS, and is connected to the first shaft W1 of the main gear set HRS. A sun gear So-P4 of the planetary gear set P4 of the auxiliary gear set ZRS is a component of a third shaft W3P4 of the auxiliary gear set ZRS, and is connected to the second shaft W2 of the main gear set HRS.

Accordingly, in the first embodiment shown in FIG. 1, the first shaft W1P4 of the auxiliary gear set ZRS is connected to the rotor R, while the second shaft W2P4 of the auxiliary gear set ZRS is connected to the first shaft W1 of the main gear set HRS. The third shaft W3P4 of the auxiliary gear set ZRS is connected to the second shaft W2 of the main gear set HRS. Alternatively, the third shaft W3P4 of the auxiliary gear set ZRS could be connected to, instead of the second shaft W2, the third or fourth shaft W3, W4 of the main gear set. However, for reasons of clarity, these alternatives are not shown in separate figures.

FIG. 2 shows a rotational speed diagram of the first embodiment of the transmission G, while a shifting diagram of the first embodiment of the transmission G is shown in FIG. 3. In FIG. 2, the rotational speeds of the four shafts W1, W2, W3, W4 of the main gear set HRS and the rotor R are plotted in a vertical direction in relation to the rotational speed of the transmission input shaft GW1. The maximum arising rotational speed of the transmission input shaft GW1 is normalized to the value of one. The distances between the four shafts W1, W2, W3, W4 of the main gear set HRS and the rotor R arise from the stationary transmission ratios of the first and second planetary gear sets P1, P2 of the main gear set HRS and the stationary transmission ratio of the planetary gear set P4 of the auxiliary gear set ZRS. Rotational speed relationships pertaining to a given operating point can be connected by a straight line.

If two shafts are connected to each other, such shafts connected to each other rotate with the same rotational speed. For reasons of clarity, such connected shafts can be shown separated from each other horizontally in the rotational speed diagram, in order to, for example, better clarify the rotational speed transfer from the upstream gear set VRS through the first, second or third power paths L1, L2, L3 to the main gear set HRS. The horizontal distance between such connected shafts that is thereby selected in the rotational speed diagram is arbitrary. Of course, the transmission ratio between such connected shafts amounts to the value of one, independent of the horizontal distance selected in the rotational speed diagram.

If, of the ring gear, bar and sun of a planetary gear set, two of such elements are connected to each other, the ring gear, bar and sun of such planetary gear set rotate with the same rotational speed. In this state, the transmission ratio relationship between the specified elements assumes the value of one. For reasons of clarity, the horizontal arrangement of the shafts connected to such elements is not shifted in the rotational speed diagram. Consequently, this condition can be seen in the rotational speed diagram by a horizontal straight line, which connects the participating shafts to each other.

The four shafts W1VS, W2VS, W3VS, W4VS of the upstream gear set VRS are also shown in the rotational speed diagram. If one of the shift elements A, B, C, D, E is locked, through the locked shift element A, B, C, D, E, a torque-transferring connection between a power path L1, L2, L3 and one of the four shafts W1, W2, W3, W4 of the main gear set HRS is established.

It can be seen from the rotational speed diagram that the first and third power paths L1, L3 undergo a transmission ratio starting from the third shaft W3VS of the upstream gear set VRS, whereas the third shaft W3VS of the upstream gear set VRS is connected to the transmission input shaft GW1. Through the first power path L1, the rotational speed is reduced in relation to the transmission input shaft GW1, while, through the third power path L3, the rotational speed is increased in relation to the transmission input shaft GW1. In the second power path L2, the rotational speed of the transmission input shaft GW1 is led without a transmission ratio directly to the first or fourth shafts W1, W4 of the main gear set HRS.

Through the shifting diagram in FIG. 3 and the rotational speed diagram in FIG. 2, the operation of the transmission G becomes clear. The locked shift elements A, B, C, D, E, F are indicated by circles in FIG. 3. By way of example, the respective transmission ratios of the individual gear steps and the gear jumps to the next higher gear to be determined from them may be taken from the shifting diagram, whereas the transmission G in such a way features a spread of 8.5. The transmission ratios arise from the stationary transmission ratios of the planetary gear sets P1, P2, P3, P4 and P5. Upon a sequential shifting operation, double gearshifts and group gearshifts can be avoided, since two adjacent gear steps jointly use one shift element. The gears of the transmission G are shown in the various lines of the shifting diagram. One column of the shifting diagram further indicates whether the electric motor EM in the relevant gear is able to deliver torque to the transmission output shaft GW2, or receive torque from it.

A first forward gear 1VM between the transmission input shaft GW1 and the transmission output shaft GW2 arises from the locking of the fifth shift element C and the sixth shift element F, a second forward gear 2VM arises from the locking of the third shift element B and the sixth shift element F, a third forward gear 3VM arises from the locking of the fourth shift element D and the sixth shift element F, a fourth forward gear 4VM arises from the locking of the third shift element B and the fourth shift element D, a fifth forward gear 5VM arises from the locking of the fifth shift element C and the fourth shift element D, a sixth forward gear 6VM arises from the locking of the first shift element A and the fourth shift element D, a seventh forward gear 7VM arises from the locking of the fifth shift element C and the first shift element A, an eighth forward gear 8VM arises from the locking of the third shift element B and the first shift element A, a ninth forward gear 9VM arises from the locking of the second shift element E and the first shift element A, a tenth forward gear 10VM arises from the locking of the third shift element B and the second shift element E, and an eleventh forward gear 11VM arises from the locking of the fifth shift element C and the second shift element E.

In an electric gear 1EM, torque is transferred to transmission output shaft GW2 solely by the electric motor EM, whereas the first, second, third, fourth and fifth shift elements A, E, B, D, C are open, and there is thus no torque-transferring connection between the transmission input shaft GW1 and the transmission output shaft GW2. The sixth shift element F is locked. The electrical gear 1EM also serves as a reverse gear, in which the electric motor EM is driven in such a manner that the rotor R assumes a negative rotational speed; that is, a reverse rotation. Thus, a separate reverse gear is not necessary.

In a first and second start mode 1S, 2S, the transmission input shaft GW1 is supplied with torque from the electric motor EM. In the first start mode 1S, all shift elements are open, except for the third shift element B. The rotor R of the electric motor EM is thereby connected directly to the transmission input shaft GW1. In the second start mode 2S, all shift elements are open, except for the fifth shift element C. The torque of the electric motor EM is thereby guided through the first power path L1 to the transmission input shaft GW1. The first and second start modes 1S and 2S are particularly relevant upon the use of the transmission G in the motor vehicle, in order to, in such a way, start an internal combustion engine VKM connected to the transmission input shaft GW1. Thereby, the transmission output shaft GW2 must be fixed in a torque-proof manner by a parking brake.

FIG. 4 schematically shows a first variant of the first embodiment of the transmission G. The structure of the upstream gear set VRS is identical to the first embodiment of the transmission G. In this first variant, the first planetary gear set P1 of the main gear set HRS features a split sun gear So-P1, which is a component of the first shaft W1 of the main gear set HRS. Between the parts of the sun gear So-P1 of the first planetary gear set P1 of the main gear set HRS, the second shaft W2 of the main gear set HRS leads to the fourth shift element D and the second shift element E. The second shaft W2 of the main gear set HRS in such a way is connectable to the first power path L1 or to the third power path L3. The second shaft W2 of the main gear set HRS is connected to the bar St-P1 of the first planetary gear set P1 and to the ring gear Ho-P2 of the second planetary gear set P2 of the main gear set HRS. One of the two parts of the sun gear So-P1 of the first planetary gear set P1 of the main gear set HRS is connected to the second shaft W2P4 of the auxiliary gear set ZRS, whereas the bar St-P4 of the planetary gear set P4 of the auxiliary gear set ZRS is a component of the second shaft W2P4 of the auxiliary gear set ZRS. The other of the two parts of the sun gear So-P1 of the first planetary gear set P1 of the main gear set HRS leads to the third shift element B, and in such a way is connected to the second power path L2. The rotor R of the electric motor EM is connected to the ring gear Ho-P4 of the planetary gear set P4 of the auxiliary gear set ZRS, which is a component of the first shaft W1P4 of the auxiliary gear set ZRS. The sun gear So-P4 of the planetary gear set P4 of the auxiliary gear set ZRS is a component of the third shaft W3P4 of the auxiliary gear set ZRS, which is connected to the third shaft W3 of the main gear set HRS. The ring gear Ho-P1 of the first planetary gear set P1 of the main gear set HRS and the bar St-P2 of the second planetary gear set P2 of the main gear set HRS are also components of the third shaft W3 of the main gear set HRS, which is connected to the transmission output shaft GW2. The sun gear So-P2 of the second planetary gear set P2 of the main gear set HRS is a component of the fourth shaft W4 of the main gear set HRS, and also features a two-part shape. Between the two parts of the sun gear So-P2 of the second planetary gear set P2 of the main gear set HRS, the third shaft W3 of the main gear set HRS leads to transmission output shaft GW2. One of the two parts of the sun gear So-P2 of the second planetary gear set P2 of the main gear set HRS leads to the first shift element A, by which the fourth shaft W4 of the main gear set HRS is connectable to the second power path L2. The other of the two parts of the sun gear So-P2 of the second planetary gear set P2 of the main gear set HRS leads to the sixth shift element F, by which the fourth shaft W4 of the main gear set HRS is fixed in a torque-proof manner against the housing GG.

Accordingly, in the first variant of the first embodiment shown in FIG. 4, the first shaft W1P4 of the auxiliary gear set ZRS is connected to the rotor R, while the second shaft W2P4 of the auxiliary gear set ZRS is connected to the first shaft W1 of the main gear set HRS. The third shaft W3P4 of the auxiliary gear set ZRS is connected to the third shaft W3 of the main gear set HRS. Alternatively, the third shaft W3P4 of the auxiliary gear set ZRS could also be connected to, instead of the third shaft W3, the second shaft W2 or the fourth shaft W4 of the main gear set HRS. The stationary transmission ratios of the participating planetary gear sets are adjusted accordingly. For reasons of clarity, such alternatives are not shown in separate figures.

The rotational speed diagram in FIG. 2 and the shifting diagram in FIG. 3 apply in equal measure to the first variant of the first embodiment of the transmission G, as shown in FIG. 4.

FIG. 5 schematically shows a second embodiment of the transmission G. In contrast to the first embodiment, an upstream gear set VRS, which solely features the first planetary gear set P3, is upstream of the main gear set HRS in the third embodiment. Moreover, in this second embodiment, all planetary gear sets P1, P2, P3, P4 are formed as negative gear sets.

The transmission input shaft GW1 is connected to the sun gear So-P3 of the first planetary gear set P3 of the upstream gear set VRS, while the ring gear Ho-P3 of the first planetary gear set P3 of the upstream gear set VRS is connected in a torque-proof manner to the transmission housing GG of the transmission G, or to a different component of the transmission G that is fixed in a torque-proof manner. In such a way, the first and second power paths L1, L2 are formed, whereas power from the transmission input shaft GW1 can be transferred to the main gear set HRS through both the first power path L1 and through the second power path L2. The second power path L2 thereby transmits to the main gear set HRS a rotational speed that is changed compared to the rotational speed of the transmission input shaft GW1, by translating the rotational speed at the transmission input shaft GW1 by the transmission ratio between the sun gear So-P3 and the bar St-P3 of the first planetary gear set P3 of the upstream gear set VRS. The first power path L1 transmits the rotational speed of the transmission input shaft GW1 without a transmission ratio to the main gear set HRS. Thereby, the sun gear So-P3 of the first planetary gear set P3 of the upstream gear set VRS is a component of a first shaft W1VS of the upstream gear set VRS, which is connected to the transmission input shaft GW1. The bar St-P3 of the first planetary gear set P3 of the upstream gear set VRS is a component of a second shaft W2VS of the upstream gear set VRS. That component on which the ring gear Ho-P3 of the first planetary gear set P3 of the upstream gear set VRS is supported is referred to below as the third shaft W3VS of the upstream gear set VRS.

The first shaft W1 of the main gear set HRS is connected to the sun gear So-P1 of the first planetary gear set P1 of the main gear set HRS. The second shaft W2 of the main gear set HRS is connected to the bar St-P1 of the first planetary gear set P1 and to the ring gear Ho-P2 of the second planetary gear set P2 of the main gear set HRS. The third shaft W3 of the main gear set HRS is connected to the ring gear Ho-P1 of the first planetary gear set P1 and to the bar St-P2 of the second planetary gear set P2 of the main gear set HRS. The fourth shaft W4 of the main gear set HRS is connected to the sun gear So-P2 of the second planetary gear set P2 of the main gear set HRS. Through this connection between the individual components of the first and second planetary gear sets P1, P2 of the main gear set HRS, the arrangement of the first, second, third and fourth shafts W1, W2, W3, W4 of the main gear set HRS in the rotational speed diagram is determined, whereas the sequence of first, second, third, fourth shafts W1, W2, W3, W4 corresponds to their sequence in the rotational speed diagram. The third shaft W3 of the main gear set HRS is connected to the transmission output shaft GW2. Alternatively, the third shaft W3 of the main gear set HRS may also be connected through an additional transmission gearing to the transmission output shaft GW2. Thereby, the sun gear So-P2 of the second planetary gear set P2 of the main gear set HRS features two parts that are separate from each other. This facilitates the connection of the transmission output shaft GW2 to the third shaft W3 of the main gear set HRS, which is arranged between the two parts of the sun gear So-P2. Of course, the rotational speed relationships are the same on both parts of the sun gear So-P2. Consequently, hereinafter, both parts of the sun gear So-P2 are referred to as one component of the same shaft, specifically the fourth shaft W4 of the main gear set HRS.

The first power path L1 is connectable through the first shift element A to the fourth shaft W4 of the main gear set HRS and through the second shift element E to the second shaft W2 of the main gear set HRS. The second power path L2 is connectable through the third shift element B to the first shaft W1 of the main gear set HRS and through the fourth shift element D to the second shaft W2 of the main gear set HRS. The first shaft W1 of the main gear set HRS is connectable through the fifth shift element C to the transmission housing GG of the transmission G, or to another torque-proof component of the transmission G, such that, with a locked fifth shift element C, the first shaft W1 of the main gear set HRS cannot assume any rotational speed. In the same manner, the fourth shaft W4 of the main gear set HRS can be fixed in a torque-proof manner through the sixth shift element F, by connecting the fourth shaft W4 through the sixth shift element F to the transmission housing GG.

In the second embodiment of the transmission G, in each case, two shift elements can be actuated by a double-acting shift device. The second and fourth shift elements E, D can be actuated through a first shift device. The third and the fifth shift elements B, C can be actuated through a second shift device. The first and sixth shift elements A, F can be actuated through a third shift device. Thereby, each of the three shift devices may occupy three states. In a first shifting state of the shift device, the first shift element allocated to the shift device is in a locked position, while the second shift element allocated to the shift device occupies an open position. In a second shifting state of the shift device, the second shift element allocated to the shift device is in a locked position, while the first shift element allocated to the shift device occupies an open position. In a third shifting state, the two shift elements allocated to the shift device occupy the open position. Based on the design of the main gear set HRS and the connection of the main gear set HRS to the electric motor EM, this allocation of a total of six shift elements A, B, C, D, E, F to only three shift devices is enabled. Moreover, this reduced number of shift devices helps to reduce the complexity of the transmission G.

In the second embodiment, the transmission G also features an electric motor EM, whereas the stator S is connected in a torque-proof manner to the transmission housing GG of the transmission G or to another torque-proof component of the transmission G, such that the stator S cannot assume any rotational speed. The rotatably mounted rotor R is connected to the sun gear So-P4 of the planetary gear set P4 of the auxiliary gear set ZRS. The sun gear So-P4 of the planetary gear set P4 of the auxiliary gear set ZRS is a component of the first shaft W1P4 of the auxiliary gear set ZRS. The bar St-P4 of the planetary gear set P4 of the auxiliary gear set ZRS is a component of the second shaft W2P4 of the auxiliary gear set ZRS and is connected to the first shaft W1 of the main gear set HRS. The ring gear Ho-P4 of the planetary gear set P4 of the auxiliary gear set ZRS is a component of the third shaft W3P4 of the auxiliary gear set ZRS and is connected to the third shaft W3 of the main gear set HRS.

In the following, a load-shifting process is described for the second embodiment by way of example. In the second forward gear, each of the second and the fourth shafts W2, W4 of the main gear set HRS forms a differential shaft, while the third shaft W3 of the main gear set HRS represents a sum shaft. Upon a shifting process from the second forward gear 2VM to the third forward gear 3VM, the fourth shift element D is locked. The sixth shift element F is open; the third shift element B is subsequently locked. If the sixth shift element F is formed as claw-shift element, the sixth shift element F must be made largely free of torque prior to opening, such that the sixth shift element F only transfers no torque or low torque. This load release of the sixth shift element F is effected by a generator torque of the electric motor EM. Thereby, at least one portion of the torque previously applied at the third shaft W3 of the main gear set HRS is maintained, by which a complete loss of torque does not arise at the transmission output shaft GW2. If the sixth shift element F is open, the second shaft W2 of the main gear set HRS becomes the sum shaft, while the first shaft W1P4 of the auxiliary gear set ZRS and the third shaft W3 of the main gear set HRS each form a differential shaft. Through the electric motor EM, a generator torque is now applied, in order to achieve a synchronization of rotational speeds between the second shaft W2VS of the upstream gear set VRS and the first shaft W1 of the main gear set HRS. This enables a locking of the third shift element B, whereas at least one portion of the torque previously applied at the third shaft W3 of the main gear set HRS is maintained. If the third shift element B is locked, the first shaft W1 of the main gear set HRS becomes the differential shaft; the shifting process is thus completed. This ensures that, during the shifting process, one part of the power flow of the transmission input shaft GW1 at the transmission output shaft GW2 can be maintained. This mode of operation applies to all embodiments.

FIG. 6 shows a rotational speed diagram in accordance with the second embodiment of the transmission G. The manner of presentation of the rotational speed plan is identical to the presentation of the first embodiment in FIG. 2.

FIG. 7 shows a shifting diagram of the transmission G in accordance with the second embodiment. Through the shifting diagram in FIG. 7 and the rotational speed diagram in FIG. 6, the operation of the second embodiment of the transmission G becomes clear. The locked shift elements A, B, C, D, E, F are indicated by circles in FIG. 7. By way of example, the respective transmission ratios of the individual gear steps and the gear jumps to the next higher gear to be determined from them may be taken from the shifting diagram, whereas the transmission G in such a way features a spread of 10.1. The transmission ratios arise from the stationary transmission ratios of the planetary gear sets P1, P2, P3, P4. Upon a sequential shifting operation, double gearshifts and group gearshifts can be avoided, since two adjacent gear steps jointly use one shift element. The gears of the transmission G are shown in the various lines of the shifting diagram. One column of the shifting diagram further indicates whether the electric motor EM in the relevant gear is able to deliver mechanical power to the transmission output shaft GW2, or receive mechanical power from it.

A first forward gear 1VM between the transmission input shaft GW1 and the transmission output shaft GW2 arises from the locking of the third shift element B and the sixth shift element F, a second forward gear 2VM arises from the locking of the fourth shift element D and the sixth shift element F, a third forward gear 3VM arises from the locking of the third shift element B and the fourth shift element D, a fourth forward gear 4VM arises from the locking of the fourth shift element D and the first shift element A, a fifth forward gear 5VM arises from the locking of the third shift element B and the first shift element A, a sixth forward gear 6VM arises from the locking of the second shift element E and the first shift element A, a seventh forward gear 7VM arises from the locking of the third shift element B and the second shift element E, and an eighth forward gear 8VM arises from the locking of the fifth shift element C and the second shift element E.

In an electric gear 1EM, torque is transferred to transmission output shaft GW2 solely by the electric motor EM, whereas all shift elements except for the sixth shift element F are open, and there is thus no torque-transferring connection between the transmission input shaft GW1 and the transmission output shaft GW2. The electrical gear 1EM also serves as a reverse gear, in which the electric motor EM is driven in such a manner that the rotor R assumes a negative rotational speed; that is, a reverse rotation. Thus, a separate reverse gear is not necessary.

In a first and second start mode 1S, 2S, torque is supplied to the transmission input shaft GW1, whereas, depending on the position of the sixth shift element F, torque can be supplied to the transmission input shaft GW1 exclusively by the electric motor EM or by the transmission output shaft GW2. If the sixth shift element F is locked, and the electric motor EM does not deliver any torque, the transmission input shaft GW1 may also be supplied with torque exclusively by the transmission output shaft GW2. This is particularly relevant when using the transmission G in a motor vehicle, in order to, in such a way, start an internal combustion engine VKM connected to the transmission input shaft GW1. If the sixth shift element F is thereby open, the transmission output shaft GW2 must be fixed in a torque-proof manner by a parking brake.

FIG. 8 schematically shows a first variant of the first embodiment of the transmission G. The upstream gear set VRS, the first and second power paths L1 and L2 and the allocation of the shift elements A, B, C, D, E, F at the four shafts W1, W2, W3, W4 of the main gear set HRS are thereby identical to the first embodiment of the transmission G shown in FIG. 5. The sun gears So-P1, So-P2 of the first and second planetary gear sets P1, P2 of the main gear set HRS are connected to each other, and are components of the first shaft W1 of the main gear set HRS. The bar St-P1 of the first planetary gear set P1 of the main gear set HRS is connected to the ring gear Ho-P2 of the second planetary gear set P2 of the main gear set HRS, and in such a way is a component of the third shaft W3 of the main gear set HRS. The ring gear Ho-P1 of the first planetary gear set P1 of the main gear set HRS is designed in two parts, whereas both parts are components of the fourth shaft W4 of the main gear set HRS. The third shaft W3 of the main gear set HRS runs between the two parts of the ring gear Ho-P1, thus leading to the transmission output shaft GW2. The bar St-P2 of the second planetary gear set P2 of the main gear set HRS is a component of the second shaft W2 of the main gear set HRS. The first and second planetary gear sets P1, P2 of the main gear set HRS are formed as negative gear sets.

The planetary gear set P4 of the auxiliary gear set ZRS is also formed as a negative gear set. The sun gear So-P4 of the planetary gear set P4 of the auxiliary gear set ZRS is a component of the first shaft W1P4 of the auxiliary gear set ZRS and is connected to the rotor R. The bar St-P4 of the planetary gear set P4 of the auxiliary gear set ZRS is a component of the second shaft W2P4 of the auxiliary gear set ZRS and is connected to the first shaft W1 of the main gear set HRS. The ring gear Ho-P4 of the planetary gear set P4 of the auxiliary gear set ZRS is a component of the third shaft W3P4 of the auxiliary gear set ZRS and is connected to the third shaft W3 of the main gear set HRS.

The rotational speed diagram in FIG. 6 and the shifting diagram in FIG. 7 apply in equal measure to the first variant of the second embodiment of the transmission G, as shown in FIG. 8. Accordingly, in the second embodiment shown in FIG. 5 and FIG. 8, the first shaft W1P4 of the auxiliary gear set ZRS is connected to the rotor R, while the second shaft W2P4 of the auxiliary gear set ZRS is connected to the first shaft W1 of the main gear set HRS. The third shaft W3P4 of the auxiliary gear set ZRS is connected to the third shaft W3 of the main gear set HRS. Alternatively, the third shaft W3P4 of the auxiliary gear set ZRS could be connected to, instead of the third shaft W3, the second or the fourth shaft W2, W4 of the main gear set HRS. The stationary transmission ratios of the participating planetary gear sets are adjusted accordingly. For reasons of clarity, such alternatives of the second embodiment are not shown in separate figures.

FIG. 9 schematically shows a second variant of the first embodiment of the transmission G. The upstream gear set VRS, the first and second power paths L1 and L2 and the allocation of the shift elements A, B, C, D, E, F at the four shafts W1, W2, W3, W4 of the main gear set HRS are thereby identical to the first embodiment of the transmission G shown in FIG. 5. In this second variant, the planetary gear set P4 of the auxiliary gear set ZRS along with the first and second planetary gear sets P1, P2 of the main gear set HRS are advantageously arranged, by connecting the ring gear Ho-P4 of the planetary gear set P4 of the auxiliary gear set ZRS along with the ring gears Ho-P1 and Ho-P2 of the first and second planetary gear sets P1, P2 of the main gear set HRS to each other. This common ring gear may be formed in one piece, thus reducing the manufacturing costs of the transmission G.

The planetary gear set P4 of the auxiliary gear set ZRS and the first planetary gear set P1 of the main gear set HRS are formed as negative gear sets. The second planetary gear set P2 of the main gear set HRS is formed as a positive gear set. The sun gear So-P4 of the planetary gear set P4 of the auxiliary gear set ZRS is a component of the first shaft W1P4 of the auxiliary gear set ZRS and is connected to the rotor R. The bar St-P4 of the planetary gear set P4 of the auxiliary gear set ZRS is a component of the second shaft W2P4 of the auxiliary gear set ZRS and is connected to the first shaft W1 of the main gear set HRS. The ring gear Ho-P4 of the planetary gear set P4 of the auxiliary gear set ZRS is a component of the third shaft W3P4 of the auxiliary gear set ZRS and is connected to the third shaft W3 of the main gear set HRS. The sun gear So-P1 of the first planetary gear set P1 of the main gear set HRS is a component of the first shaft W1 of the main gear set HRS, and meshes with the outer planetary gears of the second planetary gear set P2 of the main gear set HRS. The bar St-P1 of the first planetary gear set P1 of the main gear set HRS is connected to the bar St-P2 of the second planetary gear set P2 of the main gear set HRS, and is thereby a component of the second shaft W2 of the main gear set HRS. The sun gear So-P2 of the second planetary gear set P2 of the main gear set HRS is a component of the fourth shaft W4 of the main gear set HRS.

The first shift element A and the sixth shift element F are, as in all of the designs of the first and second embodiments, actuated by a double-acting actuator. In other words, only one actuator is provided for actuating the first shift element A and the sixth shift element F. In a first position, the actuator brings the first shift element A into a connected position, whereas the sixth shift element F is thereby in an open position. In a second position, the actuator brings the sixth shift element F into a connected position, whereas the first shift element A is in an open position. In a third position, the actuator does not bring either the first or the sixth shift element A, F into a connected position. In equal measure, the second shift element E and the fourth shift element D, along with the third shift element B and the fifth shift element C, feature such a double-acting actuator.

Through the arrangement shown in FIG. 9, it is possible that all shift elements A, B, C, D, E, F can be actuated from the outside or by bars through them.

The rotational speed diagram in FIG. 6 and the shifting diagram in FIG. 7 apply in equal measure to the second variant of the second embodiment of the transmission G, as shown in FIG. 9.

FIG. 10 schematically shows a third embodiment of the transmission G. In this third embodiment, an upstream gear set VRS is not provided. Accordingly, the transmission input shaft is connectable GW1 to the main gear set HRS only through a first power path L1. For this purpose, the transmission input shaft GW1 is connectable through the third shift element B to the first shaft W1 of the main gear set HRS and through the second shift element E to the second shaft W2 of the main gear set HRS. Through the first shift element A, the fourth shaft W4 of the main gear set HRS is fixed in a torque-proof manner. Through the fifth shift element C, the first shaft W1 of the main gear set HRS is fixed in a torque-proof manner. The first planetary gear set P1 of the main gear set HRS is formed as a positive gear set, while the second planetary gear set P2 of the main gear set HRS is formed as a negative gear set.

The first shaft W1 of the main gear set HRS is connected to the sun gear So-P2 of the second planetary gear set P2 of the main gear set HRS. The second shaft W2 of the main gear set HRS is connected to the bars St-P1, St-P2 of the first and second planetary gear sets P1, P2 of the main gear set HRS. The third shaft W3 of the main gear set HRS is connected to the ring gears Ho-P1, Ho-P2 of the first and second planetary gear sets P1, P2 of the main gear set HRS. The fourth shaft W4 of the main gear set HRS is connected to the sun gear So-P1 of the first planetary gear set P1 of the main gear set HRS.

The planetary gear set P4 of the auxiliary gear set ZRS is formed as a negative gear set. The ring gear Ho-P4 of the planetary gear set P4 of the auxiliary gear set ZRS is a component of the first shaft W1P4 of the auxiliary gear set ZRS and is connected to the rotor R of the electric motor EM. The stator S of the electric motor EM is connected to the housing GG of the transmission G and is thus fixed in a torque-proof manner. The bar St-P4 of the planetary gear set P4 of the auxiliary gear set ZRS is a component of the second shaft W2P4 of the auxiliary gear set ZRS and is connected to the first shaft W1 of the main gear set HRS. The sun gear So-P4 of the planetary gear set P4 of the auxiliary gear set ZRS is a component of the third shaft W3P4 and is connected to the fourth shaft W4 of the main gear set HRS. The third shaft W3 of the main gear set HRS is connected to the transmission output shaft GW2.

Accordingly, in the third embodiment shown in FIG. 10, the first shaft W1P4 of the auxiliary gear set ZRS is connected to the rotor R, while the second shaft W2P4 of the auxiliary gear set ZRS is connected to the first shaft W1 of the main gear set HRS. The third shaft W3P4 of the auxiliary gear set ZRS is connected to the fourth shaft W4 of the main gear set HRS. Alternatively, the third shaft W3P4 of the auxiliary gear set ZRS could also be connected to, instead of the fourth shaft W4, the second or the third shaft W2, W3 of the main gear set HRS. For reasons of clarity, such alternatives of the third embodiment are not shown in separate figures.

FIG. 11 shows a rotational speed diagram in accordance with the third embodiment of the transmission G. The manner of presentation of the rotational speed plan is identical to the presentation of the first embodiment in FIG. 2.

FIG. 12 shows a shifting diagram of the transmission G in accordance with the third embodiment. Through the shifting diagram in FIG. 11 and the rotational speed diagram in FIG. 12, the operation of the third embodiment of the transmission G becomes clear. The locked shift elements A, B, C, E are indicated by circles in FIG. 12. By way of example, the respective transmission ratios of the individual gear steps and the gear jumps to the next higher gear to be determined from them may be taken from the shifting diagram, whereas the transmission G in such a way features a spread of 5.8. The transmission ratios arise from the stationary transmission ratios of the planetary gear sets P1, P2, P4. Upon a sequential shifting operation, double gearshifts and group gearshifts can be avoided, since two adjacent gear steps jointly use one shift element. The gears of the transmission G are shown in the various lines of the shifting diagram. One column of the shifting diagram further indicates whether the electric motor EM in the relevant gear is able to deliver mechanical power to the transmission output shaft GW2, or receive mechanical power from it.

A first forward gear 1VM between the transmission input shaft GW1 and the transmission output shaft GW2 arises from the locking of the first shift element A and the third shift element B, a second forward gear 2VM arises from the locking of the first shift element A and the second shift element E, a third forward gear 3VM arises from the locking of the third shift element B and the second shift element E, and a fourth forward gear 4VM arises from the locking of the second shift element E and the fifth shift element C.

In an electric gear 1EM, torque is transferred to transmission output shaft GW2 solely by the electric motor EM, whereas all shift elements except for the first shift element A are open, and there is thus no torque-transferring connection between the transmission input shaft GW1 and the transmission output shaft GW2. The electrical gear 1EM also serves as a reverse gear, in which the electric motor EM is driven in such a manner that the rotor R assumes a negative rotational speed; that is, a reverse rotation. Thus, a separate reverse gear is not necessary.

In the first and second start modes 1S, 2S, the transmission input shaft GW1 is supplied with torque. In the first start mode 1S, the first shift element A and the third shift element B are locked, by which the fourth shaft W4 is fixed in a torque-proof manner. If, in the first start mode 1S, torque is applied at the transmission output shaft GW2, power in such a way can be transferred from the transmission output shaft GW2 to the transmission input shaft GW1. The electric motor EM may also add power. With the use of the transmission G in a motor vehicle with an internal combustion engine VKM, the first start mode 1S can be used for the towed takeoff of the internal combustion engine VKM. In the second start mode 2S, all shift elements are open, except for the third shift element B. If a parking brake, which is connected to the transmission output shaft GW2, is applied, the third shaft W3 of the main gear set HRS is thereby fixed in a torque-proof manner. Through the electric motor EM, power may thus be transferred from the first shaft W1P4 of the auxiliary gear set ZRS to the transmission input shaft GW1, in order to, in such a way, start an internal combustion engine VKM connected to the transmission input shaft GW1.

FIG. 13 schematically shows a hybrid drive train of a motor vehicle. The transmission G contained therein corresponds to the first embodiment of the transmission G, whereas this is to be regarded merely as an example. Alternatively, the second or third embodiments of the transmission G, G form a component of the hybrid drive train. A rotatable rotor R2 of an auxiliary electric motor SG is connected to the transmission input shaft GW1, while the stator S2 of the auxiliary electric motor SG is fixed in a torque-proof manner to the transmission housing GG of the transmission G or to another torque-proof component of the transmission G. Through a rotational vibration damper RD, an internal combustion engine VKM is connected to the transmission input shaft GW1. The transmission output shaft GW2 is connected to an axle drive AG. Starting from the axle drive AG, the torque that applies at the transmission output shaft GW2 is distributed to wheels W of the motor vehicle. In engine mode of the electric motor EM, electric power is supplied to the stator S through a power inverter INV. In generator mode of the electric motor EM, the stator S supplies electric power to the power inverter INV. Thereby, the power inverter INV converts the DC voltage of a battery BAT into an AC voltage suitable for electric motor EM, and vice versa. Thereby, the auxiliary electric motor SG may likewise be supplied with electric power through the power inverter INV. Alternatively, the auxiliary electric motor SG may also be connected to a different power supply, for example, to a low-voltage electrical system of the motor vehicle.

REFERENCE SIGNS

G Transmission

GW1 Transmission input shaft

GW2 Transmission output shaft

HRS Main gear set

ZRS Auxiliary gear set

VRS Upstream gear set

EM Electric motor

R Rotor of the electric motor

S Stator of the electric motor

SG Auxiliary electric motor

R2 Rotor of the auxiliary electric motor

S2 Stator of the auxiliary electric motor

RD Rotational vibration damper

VKM Internal combustion engine

INV Power inverter

BAT Battery

P1 First planetary gear set of the main gear set

P2 Second planetary gear set of the main gear set

P3 First planetary gear set of the upstream gear set

P4 Planetary gear set of the auxiliary gear set

P5 Second planetary gear set of the upstream gear set

W1 First shaft of the main gear set

W2 Second shaft of the main gear set

W3 Third shaft of the main gear set

W4 Fourth shaft of the main gear set

W1VS First shaft of the upstream gear set

W2VS Second shaft of the upstream gear set

W3VS Third shaft of the upstream gear set

W4VS Fourth shaft of the upstream gear set

W1P4 First shaft of the auxiliary gear set

W2P4 Second shaft of the auxiliary gear set

W3P4 Third shaft of the auxiliary gear set

A First shift element

E Second shift element

B Third shift element

D Fourth shift element

C Fifth shift element

F Sixth shift element

So-P1 Sun gear of the first planetary gear set of the main gear set

St-P1 Bar of the first planetary gear set of the main gear set

Ho-P1 Ring gear of the first planetary gear set of the main gear set

So-P2 Sun gear of the second planetary gear set of the main gear set

St-P2 Bar of the second planetary gear set of the main gear set

Ho-P2 Ring gear of the second planetary gear set of the main gear set

So-P3 Sun gear of the first planetary gear set of the upstream gear set

St-P3 Bar of the first planetary gear set of the upstream gear set

Ho-P3 Ring gear of the second planetary gear set of the upstream gear set

So-P4 Sun gear of the planetary gear set of the auxiliary gear set

St-P4 Bar of the planetary gear set of the auxiliary gear set

Ho-P4 Ring gear of the planetary gear set of the auxiliary gear set

So-P5 Sun gear of the second planetary gear set of the upstream gear set

St-P5 Bar of the second planetary gear set of the upstream gear set

Ho-P5 Ring gear of the second planetary gear set of the upstream gear set

L1 First power path

L2 Second power path

L3 Third power path

1VM-11VM First to eleventh forward gears

1EM Electric gear

1S First start mode

2S Second start mode

AG Axle drive

W Wheel 

1. Transmission (G) with a transmission input shaft (GW1) and a transmission output shaft (GW2), a main gear set (HRS), an auxiliary gear set (ZRS), and an electric motor (EM) with a rotor (R) and a stator (S), whereas the transmission (G) features at least one power path (L1, L2, L3) between the transmission input shaft (GW1) and the main gear set (HRS), whereas the main gear set (HRS) features a first and a second planetary gear set (P1, P2) with a total of four shafts (W1, W2, W3, W4) designated in the order of rotational speeds as the first, second, third and fourth shafts, whereas the at least one power path (L1, L2, L3) is connectable through at least one shift element (A, B, C, D, E) to at least one of the four shafts (W1, W2, W3, W4) of the main gear set (HRS), whereas the third shaft (W3) of the main gear set (HRS) is connected to the transmission output shaft (GW2), whereas the auxiliary gear set (ZRS) features a planetary gear set (P4) with a first, second and third shaft (W1P4, W2P4, W3P4), and whereas the first shaft (W1P4) of the auxiliary gear set (ZRS) is connected to the rotor (R). characterized in that the second shaft (W2P4) of the auxiliary gear set (ZRS) is constantly connected to the first shaft (W1) of the main gear set (HRS), and whereas the third shaft (W3P4) of the auxiliary gear set (ZRS) is constantly connected to the second, third or fourth shaft (W2, W3, W4) of the main gear set (HRS). 2-16. (canceled) 